The present invention relates to pentafluorothiobenzamidoacetonitrile derivatives. The invention also relates to pharmaceutical compositions containing such compounds and their use in treating parasitic infestations.
There is a continuing need to provide new agents for the control of parasitic infestations that present a threat to human and animal health. In particular, new agents are needed to manage endoparasitic infestations in livestock animals due to the increasing prevalence of parasites, and in particular nematodes, that are resistant to many of the agents currently approved for this indication.
European patent application EP-0953565-A2 (Nihon Nohyaku Co. Ltd.) describes a genus of amidoacetonitrile derivatives and reports that these compounds have insecticidal properties. International patent application WO-2002/060257-A1 (Novartis AG) records that the same genus is active against endoparasites such as helminths. Related genera and subgenera are discussed in WO-2002/049641-A2 (Novartis), WO-20021050052-A1 (Syngenta), WO-2005/044784-A1 (Novartis), WO-2005/121075-A1 (Novartis) and WO-2006/043654 (Nihon). The mechanism by which these agents act has not yet been fully elucidated.
There remains a need for further compounds as alternative or improved therapeutic agents. Preferred compounds should be potent parasiticidal agents while presenting little or no toxicity to the host animal, and should exist in a physical form that is stable, non-hygroscopic and easily formulated. They should have high bioavailability, be metabolically stable and possess favourable pharmacokinetic properties. When intended for use in livestock animals, the compounds should be cleared in such a manner as to minimise withholding times without presenting a risk to the food chain.